Ionic Liquid-Assisted MAPbI<sub>3</sub> Nanoparticle-Seeded Growth for Efficient and Stable Perovskite Solar Cells
Md. Shahiduzzaman, LiangLe Wang, Shoko Fukaya, Ersan Y. Muslih, Atsushi Kogo, Masahiro Nakano, Makoto Karakawa, Kohshin Takahashi, Koji Tomita, Jean‐Michel Nunzi, Tsutomu Miyasaka, Tetsuya Taima
Abstract
With the rapid improvement of perovskite solar cells (PSCs), long-life operational stability has become a major requirement for their commercialization. In this work, we devised a pristine cesium–formamidinium–methylammonium (termed as CsFAMA) triple-cation-based perovskite precursor solution into the ionic liquid (IL)-assisted MAPbI3 nanoparticles (NPs) through a seeded growth approach in which the host IL-assisted MAPbI3 NPs remarkably promote high-quality perovskite films with large single-crystal domains, enhancing the device performance and stability. The power conversion efficiency (PCE) of the MAPbI3 NP-seeded growth of MAPbI3 NPs/CsFAMA-based PSCs is as high as 19.44%, which is superior to those of MAPbI3 NPs and pristine CsFAMA films as the photoactive layer (9.52 and 17.33%, respectively). The long-term light-soaking and moisture stability of IL-aided MAPbI3 NPs/CsFAMA-based devices (non-encapsulated) remain above 90 and 80%, respectively, of their initial output after 2 h of light illumination (1 sun) and 6000 h storage at ambient with a relative humidity range of 30–40%. The use of the IL-assisted MAPbI3 NP-seeded growth for PSCs is a significant step toward developing stable and reliable perovskite photovoltaic devices.